Joint editing of documents on-line is a fairly common activity. When a document is edited in real time by more than one person while they are discussing the document, if each user is allowed to edit the document freely at any time or if the user has acquired a right to exclude others, there is a possibility of changing document portions unrelated to the content about which they are discussing. In this case, the results of the joint edit cannot be reflected in the document until the proper authority does so.
Another technique involves pre-registering part of a document as editable by a specific user. This is not only inconvenient, but also limits the number of users able to edit each portion of the document, resulting in insufficient discussions as a whole. In some cases a lead user can permit a specific user to make a change. However, the change must be permitted on a user-by-user basis, and this may make it difficult to reflect the content in each portion of the document.